Fix bug in detection of CPU throttling
Fix bug in detection of CPU throttling

glob.glob actually does not provide a way to match
for example either "2" or "10",
the pattern we created in such a case would match either "2", "1", "0", or ",".
This could lead to matching the wrong cores
when cores with multi-digit numbers were used.

dbeyer/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,ultimate-pa/benchexec,dbeyer/benchexec,dbeyer/benchexec,ultimate-pa/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,dbeyer/benchexec